In the fighting of wildfires, a variety of fire suppression materials are known, as well as equipment for delivery of such fire suppression materials. Perhaps the most common fire suppression material is liquid water. Water can be delivered on a fire, or a space which is to be treated in advance to stop the progression of a fire, in a variety of different ways. For instance, hoses can deliver water from a stationary source such as a fire hydrant, or from a mobile source such as a fire truck. Water tenders are known which can deliver water from tanks on the vehicle to ground adjacent the vehicle, with or without use of hoses.
Aircraft can also be used for delivery of water for fire suppression. While fixed wing aircraft are sometimes used, most often water is delivered by rotating wing aircraft. In a typical such system, a bucket is suspended from a helicopter. The bucket can be dipped into a water reservoir to fill the bucket or be pumped into the bucket. The helicopter then transports the bucket to an area to be treated with the water. A floor or other portion of the bucket is openable to drain the bucket of water and treat the area beneath the bucket. The helicopter then repeats the filling procedure for additional treatment of areas with water. One such line of buckets is provided by S.E.I. Industries, Ltd. of Delta, British Columbia, Canada under the trademark BAMBI BUCKET.
Fire suppression gels are known in the art to have a greater effectiveness in suppressing fire than water alone. Such gels typically begin in the form of a concentrate which can be a solid or a liquid having a high concentration of gel compositions therein. This gel is hydrated to a most desirable water and gel mixture ratio and then is applied to an area to either directly extinguish fire or to treat an area in advance of an approaching fire to impede the progress of the fire, or otherwise suppress fire in the area being treated. Such fire suppression gels, when mixed with water, greatly enhance the effectiveness of the water in suppressing the fire. In particular, the water in the hydrated gel coatings does not evaporate as quickly as water alone, thus maintaining a coating of the area to be treated and discouraging the combustion of combustible materials in the area being treated. One such polymer material is provided under the trademarks FIREWALL ULTRA, provided by BroadRange Wildland Fire Chemicals of Cold Springs, Calif. and FIREWALL II, provided by Eco FireSolutions of Carmichael, Calif., in the form of a liquid emulsion.
While the use of such fire suppression gels is known when treating an area with fire hoses either coupled to stationary sources of water or hydrated gel; or from mobile ground sources (such as tanker trucks), a need exists for an effective airborne fire suppression gel delivery system. While a bucket or other container filled with hydrated gel could be utilized, such an arrangement would be inefficient in that frequent return trips to a source of hydrated gel would be required. Accordingly, a need exists for a system for onboard manufacture of such a water and fire suppression gel mixture on an airborne platform.
Furthermore, water buckets and fixed tanks deliver water to an area to be treated for fire suppression in a rather imprecise manner, merely involving the opening of a lower portion of the bucket or tank. While generally effective for water having a lower fire suppression capacity, with the utilization of fire suppression gel it is desirable that a mixture of water and fire suppression gel be applied to an area to be treated in a precise manner to maximize the fire suppression capability of the gel and minimize the number of repeat trips required and maximize the length of fire line being treated by an airborne vehicle. Thus a need exists for polymer gel emulsion discharge options other than (or augmenting) bucket dumping.
Because various scenarios are presented for the operator of a firefighting aircraft, firefighting systems including those which feature polymer gel emulsion addition to water benefit from multiple selectable modes of operation. A need exists for systems which can either simultaneously draw water into the bucket and dose the water with polymer gel emulsion, or separately first draw the water into the bucket without addition of polymer gel emulsion, followed by a later step of converting the water to a combination of water and activated polymer gel emulsion before discharge. Such systems would also benefit from being able to discharge purely water in certain circumstances.
Building fires were fought for much of history by people flinging buckets of water into burning rooms and buildings. Any nearby source of water could be used and the water was generally delivered at least in the vicinity of the fire. The random nature of where the water actually ended up landing, as compared to where it was most needed, limited its effectiveness. Nonetheless, it was sometimes successful, particularly on relatively small fires. And better than doing nothing at all.
The advent and application of pump and nozzle technologies greatly improved firefighting efficiency and capability. Communities were justly proud of having modern man-powered hand pumpers. The pumpers produced a pressurized stream that could be directed to reach and attack fires without having the limitations of flinging bucket loads in the fire's general direction. Greater volumes of water could be intentionally put were it was useful and effective. The element of the random pattern in which varying amounts of water landed was removed. A major technological bridge had been crossed.
The arrival of first steam and then internal combustion power enhanced these technologies further. They allowed pumps to create stronger, larger and more numerous pressurized streams. The ability to put water were it was most needed still remained the key component. Improved pumping capacity facilitated and expanded the overall capability but was not, in and of itself, very useful without the improved, more accurate delivery method.
Helicopter delivery systems for use on wildland fires (while better than nothing) are stuck in the antiquated bucket brigade era. They fling an undirected volume at the fire. They rely on gravity alone to place their loads without being able to have much control over the placement on the ground. The patterns created lack much uniformity—over treating some areas and under treating others—in a somewhat random manner. They spread out their loads to the point where inconsistent, ineffective distribution exists requiring the dumping of overly large amounts to compensate for this shortcoming. Just like the bucket brigades of old.
Pressurizing the contents of helicopter buckets by using a pump to deliver it downward, forming coherent streams with nozzles and aiming them in a consistent way at the ground offers the same potential to advance wildland firefighting. This advance would be similar to what occurred earlier in the adoption of those technologies for fighting building fires. And it offers an opportunity to use something more effective than water on fires as well.
The hardware components and technological knowhow already exists to allow these technologies to be added to existing helicopter buckets. Equipment installed to upgrade existing bucket brigade era systems can bring the benefits of these recognized firefighting advantages to aerial delivery. These upgrades also allow for improvement over plain water drops, leveraging the results of the changes. They allow the use of polymer. The airborne production of a valuable firefighting agent as a replacement for plain water, thus further enhancing the benefits of such a system.
Water quickly runs off of most plant materials but gel does not. Gel can keep many multiples of the amount of water in fuels than can plain water. According to this invention, gel can be produced immediately from buckets containing only water and without the gel being introduced into the bucket. Without risk, refills can be made from any water source available for conventional dipping, including locally existing sources, adding flexibility.
All in all, the opportunity exists to improve firefighting, reduce costs and address the shortcomings of the present hardware and the type of firefighting agent used by progressing beyond the bucket brigade age that firefighting aircraft are stuck in. The results of seemingly simple improvements are evident in how building fires are fought and controlled today as contrasted with what was possible in the bucket brigade era. The technological bridge that was crossed long ago for fighting building fires can also now be crossed for aircraft operating on wildland fires, exploiting and expanding the advantages found in their present use.